<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>box</title>
    <style>
        .box {
            background-color: gray;
            width: 500px;
            height: 300px;
            /*padding: 10px;  !*四个方向内边距全是10px*!*/
            /*padding: 10px 20px 30px 40px;  !*上右下左*!*/
            /*padding: 20px 40px;  !*上下20px，左右40px*!*/
            padding-top: 10px;  /*上*/
            padding-bottom: 20px;  /*下*/
            padding-left: 30px;  /*左*/
            padding-right: 40px;  /*右*/
            border-top: 5px solid darkcyan;
            border-bottom: 5px dotted purple;
            border-left: 5px dashed darkgoldenrod;
            /*margin: 50px;*/
            margin: 10px auto;  /*外边距左右设置为auto，则居中*/
        }
    </style>
</head>
<body>
<div class="box">
    达内云计算 cloud computing
</div>
</body>
</html>